Check that there is not excess movement or slop in the rear transmission bushing where the drive shaft yoke fits.

Lorena, Texas (South of Waco)

I did have a look at the Yoke when I had it out. If there was excessive Play in the Bushing would I not see indications on the Yoke i.e Wear Marks where its been moving? Yoke was clean. Something else to check anyway. Thanks

  

My bushing was worn but not through to the cast housing metal and the yoke showed no signs of wear.

Ok. I will keep that Suggestion in mind. I did find a couple of Places where the Exhaust was contacting the Frame. Not much contact but I guess when Pipes Expand with Heat and Motor Torque contact may be more than it looks like. Going Thursday to get the Exhaust Tweeked for more Clearance. See if that makes a Difference. Go from there. Thanks

  

I am going to have the Car up on a Hoist Thursday so I will get a chance to check Extension Housing Bushing. What am I looking for exactly? If I try and move the Yoke going into the Transmission up and down and Sideways there should not be any movement? Is this Correct? Thanks.

  

i had to chase down a similar noise years ago and it turned out that  the exhaust needed a balance pipe between the two pipes. it fixed the  problem.this may help??

Yes, move it in all directions. It was harder to move against the pressure of the seal and it was much more noticeable after the seal was removed. And I don't know what is an exceptible tolerance is. 

The fact that it changes Could indicate the pipes are contacting something on the frame or crossmember because the engine is rocking slightly under load OR maybe the drive shaft has thrown off the balance weight. Either could cause the problem. Pipes are the most likely, Look carefully for signs of rubbing.




Frank/Rebop

Bristol, In ( by Elkhart) 

I had it back to the Shop that did the Exhaust. There's no Contact now. I did try to check the rear Transmission Bushing. Seems to have minimal movement. I don't know how much difference the Seal makes as far as telling how much play there is. Still have Vibration. Seems to be most noticeable between 35-50, Past 50 it tapers off. Still trying to track the Cause. As I mentioned shifting to Neutral Vibration disappears.  

  

Did You find the Vibration was consistent at all Speeds?  I am going to try and borrow the Driveshaft from my Friends 56 which is Automatic like Mine. See if it makes any difference indicating it may be a Driveshaft Balance or untrue(bent) problem. Over 50 the Vibration Tapers off which is why I am asking if You found the Vibration at all Speeds with the worn Bushing.